im an idiot with a pet snake!!

first off, let me start by saying this is my first pet ever. i was told that cornsnakes are low maintenance pets and i figured it would be good for me since i wanted an animal but never had one before and i dont have a lot of time on my hands to care for one. and im aware that i could have looked for advice earlier or given him to a better owner or a million other things. i dont need the criticism or anything about how i have cared for him. the point is, that im looking for help NOW, and would just like any tips or information that you guys can offer.
i have had my snake for 3 years this month, and he is not nearly the size of any other snake that i have seen his age. (im actually not sure of the gender, i just use male pronouns) I got him as a hatchling, and for about the first month, i could not get him to eat at all because he would not (and still wont) take anything frozen. it took me so long to find a store in my area that sold live mice small enough for him to eat. i would feed him 3-4 pinkys every other week. i was told that cornsnakes will eat as much food as they can even if they dont need to, so i was afraid to feed him any more than that. he did grow and shed about once a month, but after a while, i became inconsistent with his feedings. i started to feed him fuzzies after about a year and he still gets fuzzies (3-4 every other week). right now he is 2 feet long, maybe a little longer, and almost the size of a quarter in diameter at his widest point. he always has fresh water, a heat lamp on one side of the 20 gallon tank, a hiding place, and a branch to climb on. how big should my snake be at this age? if i feed him more will he grow, or is he beyond his growth stage at this age? should i try to feed him larger mice? im afraid that he may not be able to eat a hopper

At that size, he should be able to easily eat a hopper. The prey item (and don't feed so many! D should be about 1 1/2 times as big as the widest part of your snake's body.

What are the temperatures? How are you measuring them? How are you controlling them?

Yeah I would think the main issue is mouse size. Should have been moved up to fuzzy well before a year in age. They don't grow as much on pinkies until you start moving them up to larger mice. Like Megan said, get a mouse that is roughly 1.5 times the width of the widest part of the snake (instead of feeding it multiple small items). Should leave a noticeable feeding lump, their jaws can handle it. Just feed it that size, 1 mouse roughly every 7 days. Moving up the mouse size as the snake gets bigger until it is on adult size mice.

Is he still only taking live food? If so, moving up to the larger mice increases the risk of your snake getting bitten. It is hard, but not impossible to convert a live-feeder to frozen-thawed, but you would be better off stunning larger mice with a sharp blow to the back of the skull before feeding them to him, while they are twitching.

Also, I would suggest having an under-tank heater instead of the overhead lamp. The belly heat will help him digest his food better, especially with the larger prey items that you'll be moving up to. You can get a thermometer and thermostat and you'll be set-up on his heating/housing requirements.

He should be able to handle a hopper a week without a problem, it can be scary bumping up but we eventually we all realize that a snake can open those jaws pretty damn wide. Just make sure, as others have noted, that it's 1-1.5 the size of the widest part of his body.

Increasing the food size will allow him to grow, and shed more regularly as well.

Lol, one mouse at a time.

Can we get a pic of the guy? My first snake was far smaller than my current ones at the same age, and as long as you're not seeing the spine and feeling ribs, your snake may just be a little guy. Like everyone has said, there are lots of ways to get him to switch over to f/t food, though some rare corns may never make the switch. I would feed him a few live hoppers (one a week) and then try p/k, eventually moving to f/t.

I am far from being an expert but you should be feeding him about every 7 days with 1 hopper.. As it has been said, some snakes tend to be on the smaller side but maybe with the increased feedings he will grow a bit more.

2 of my cornsnakes were on live prey when I bought them. I have never offered either live food since bringing them home and had no problems switching them first to F/K, then to F/T.

Personally I have not found any of my corns to be picky eaters, they all eat F/K or F/T rats, mice, rabbit pinkies and small chicks (the last two are only fed to my snakes that are 4' or more.

Just checking? When you tried frozen, Did you thaw the mouse out and warm it to normal body temperature?